I was curious how people have been infected in the past, although I'm sure not everyone wants to admit it if it's happened The poll itself is anonymous. Fair's fair, so I'll start off: 1. When I was about ten a floppy disk from a friend infected our computer with a boot sector virus, which made the computer unbootable. Looking back, it was fun having to learn how to repair the boot sector and disinfect the virus - just like a puzzle in an adventure game. It taught me to always scan floppy disks, and later USB sticks. 2. In the late 90s, a male friend of my older sister tricked her into running Back Orifice (if anyone remembers that backdoor remote admin program!). Dirty voyeur. Somehow I figured it out and disabled it, then tracked the access attempts to his IP address. His mum was mortified when she was told! 3. Early 2000s, a few of the freeware programs from well known publishers came with hidden spyware - ergo why most of us started using Spybot: S&D. This is what I mean by spyware in the poll; I'm sure many remember Aureate and Alexa. 4. I admit at some stage to stupidly running a file that contained a trojan when really I knew better; unfortunately curiosity as well as false negatives from AV scans overrode common sense in that case. Last time I did anything like that without first managing the risk intelligently, and it's been a long time since I've been infected. I decided to go by the infectors themselves (virus, trojan, etc), rather than so much the vectors (email attachments, USB stick, etc) - otherwise it would be a long and disorganised poll. The vectors are inherent anyway, e.g. a trojan is always going to trick in one way or another; a worm is always going to propagate itself with certain methods, etc. I put application exploits as a category of their own as even though the payload is usually a trojan of some sort, the trojan executes without the user doing anything other than using an internet facing application or visiting a webpage that hosts an exploit kit.